Process for Reconditioning Semiconductor Surface to Facilitate Bonding

Abstract

A non-abrading method to facilitate bonding of semiconductor components, such as silicon wafers, that have micro structural defects in a bonding interface surface. In a preferred method, micro structural defects are removed by forming an oxide layer on the bonding interface surface to a depth below the level of the defect, and then removing the oxide layer to expose a satisfactory surface for bonding, thereby increasing line yield and reducing scrap triggers in fabrication facilities.

Description

BACKGROUND OF THE INVENTION[0001]This invention relates in general to valves and to semiconductor electromechanical devices, and in particular, to micromachined components formed from layers of a semiconductor material, such as silicon, bonded together.[0002]MEMS (micro electro mechanical systems) are a class of systems that are physically small, having features or clearances with sizes in the micrometer range or smaller (i.e., smaller than about 10 microns). These systems have both electrical and mechanical components. The term “micro machining” is commonly understood to mean the production of three-dimensional structures and moving parts of MEMS devices. MEMS originally used modified integrated circuit (e.g., computer chip) fabrication techniques (such as chemical etching) and materials (such as silicon semiconductor material) to micro machine these very small mechanical devices. Today there are many more micro machining techniques and materials available. The term “MEMS device” a...

AI Technical Summary

Benefits of technology

[0004]The invention relates to a method to facilitate bonding of semiconductor components, such as silicon wafers, that have micro structural defects on a bonding interface surface, for example due to exposure to wet or dry chemical micromachining processes while creating structures on or in the semiconductor material. Many bonding processes require that a substrate bonding interface surface be substantially free of defects to facilitate the bonding of the surface to the surface of another substrate with highly reliable bonding strength. Fusion bonding is a process that is particularly susceptible to bond failure due to poor surface quality. Semiconductor wafers that have undergone extensive micromachining processes may have bonding interface surfaces that have micro structural defects caused by these micromachining processes. In a novel method, wafers which have such defects in interface surfaces, and which otherwise might have to be discarded as scrap, may be reconditioned to remove these defects using a non-abrading process. One example of such a non-abrading process in a method which includes forming an oxide layer (such as a silicon dioxide layer) on the bonding interface surface to a depth below the level of the defect, and then removing the oxide or silicon dioxide layer to expose a satisfactory surface for bonding, thereby increasing line yield and reducing scrap triggers in fabrication facilities.

Problems solved by technology

Fusion bonding is a process that is particularly susceptible to bond failure due to poor surface quality.

Semiconductor wafers that have undergone extensive micromachining processes may have bonding interface surfaces that have micro structural defects caused by these micromachining processes.

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